/*
 * Copyright (c) 2006-2011 Nuxeo SA (http://nuxeo.com/) and others.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Anahide Tchertchian
 */
package org.eclipse.ecr.core.api.externalblob;

import java.io.Serializable;
import java.util.Map;

import org.eclipse.ecr.core.api.Blob;
import org.eclipse.ecr.core.api.model.PropertyException;

/**
 * Interface to implement when defining a way to get a {@link Blob} that is not stored at
 * the usual place handled by the repository.
 * <p>
 * This is done storing a string instead of a blob, using a prefix that makes it
 * possible to find the adapter in charge of retrieving the file. It makes it
 * also possible to use the same adapter implementation for different
 * configurations, in conjunction with properties.
 * <p>
 * The string will look something like "fs:file/foo.odt", "fs" being the prefix,
 * and "file/foo.odt" being the local name, with all the needed information to
 * retrieve the actual file for this adapter.
 *
 * @author Anahide Tchertchian
 */
public interface ExternalBlobAdapter extends Serializable {

    String PREFIX_SEPARATOR = ":";

    /**
     * Returns the prefix to use as marker for this adapter
     */
    String getPrefix();

    /**
     * Sets the prefix to use as marker for this adapter
     */
    void setPrefix(String prefix);

    /**
     * Return specific properties for this adapter. Can be used for whatever
     * useful property.
     */
    Map<String, String> getProperties();

    /**
     * Return property with gievn name.
     * <p>
     * Returns null if no property value is found.
     */
    String getProperty(String name);

    /**
     * Set specific properties for this adapter. Can be used for whatever useful
     * property.
     */
    void setProperties(Map<String, String> properties);

    /**
     * Retrieves the blob for given uri.
     *
     * @param uri the uri describing what adapter handles the file and the
     *            needed info to retrieve it.
     * @return the resolved blob.
     * @throws PropertyException if the blob cannot be retrieved (if adapter
     *             cannot retrieve it or if file is not found for instance)
     */
    Blob getBlob(String uri) throws PropertyException;

}